diff --git a/android/contrib/tools/do-compile-ffmpeg.sh b/android/contrib/tools/do-compile-ffmpeg.sh
index d6b3ba639d..be50509e5e 100755
--- a/android/contrib/tools/do-compile-ffmpeg.sh
+++ b/android/contrib/tools/do-compile-ffmpeg.sh
@@ -212,12 +212,12 @@ echo ""
 echo "--------------------"
 echo "[*] check ffmpeg env"
 echo "--------------------"
-export PATH=$FF_TOOLCHAIN_PATH/bin/:$PATH
+export PATH="$FF_TOOLCHAIN_PATH/bin/:$PATH"
 #export CC="ccache ${FF_CROSS_PREFIX}-gcc"
 export CC="${FF_CROSS_PREFIX}-gcc"
-export LD=${FF_CROSS_PREFIX}-ld
-export AR=${FF_CROSS_PREFIX}-ar
-export STRIP=${FF_CROSS_PREFIX}-strip
+export LD="${FF_CROSS_PREFIX}-ld"
+export AR="${FF_CROSS_PREFIX}-ar"
+export STRIP="${FF_CROSS_PREFIX}-strip"
 
 FF_CFLAGS="-O3 -Wall -pipe \
     -std=c99 \
diff --git a/android/contrib/tools/do-detect-env.sh b/android/contrib/tools/do-detect-env.sh
index 36d64fdc3e..6fe06f19c6 100644
--- a/android/contrib/tools/do-detect-env.sh
+++ b/android/contrib/tools/do-detect-env.sh
@@ -90,6 +90,11 @@ case "$UNAME_S" in
     Darwin)
         export IJK_MAKE_FLAG=-j`sysctl -n machdep.cpu.thread_count`
     ;;
+    Linux)
+        if which nproc >/dev/null; then
+            export IJK_MAKE_FLAG=-j`nproc`
+        fi
+    ;;
     CYGWIN_NT-*)
         IJK_WIN_TEMP="$(cygpath -am /tmp)"
         export TEMPDIR=$IJK_WIN_TEMP/